Einstein's Starting Point

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by guoliang liu</i>
<br />Because the fine structure constant should be invariant, the elementary charge and the electric constant in vacuum should be invariant in the gravitational field<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">We need a complete physical model for these entities before we can make such statements. In fact, the model I proposed recently in the Meta Research Bulletin ("The structure of matter in the Meta Model") calls for variation in at least the strength of Coulomb force accompanying variations in gravitational potential, because both depend on elysium (light-carrying medium) density.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">if the speed of light is a function of the gravitational potential, does that mean the Planck's constant and the magnetic constant in vacuum are functions of the gravitational potential as well?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Again, that is model-dependent. But probably yes.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Could you show me the function describing how the speed of light slows down in a gravitational field?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">See "Gravitational force vs. gravitational potential" at metaresearch.org/cosmology/gravity/gravity.asp See text for link to a free PowerPoint viewer. -|Tom|-

Dear Mr. Flandern,
Thank you for spending time on my question.
The sun and the earth both can be a preferred frame, but how do you define the boundary between them?
Do you think that a reference frame with zero gravitational potential can be used as the absolute still reference frame? In this frame, the speed of light will reach a maximum limit.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by guoliang liu</i>
<br />The sun and the earth both can be a preferred frame, but how do you define the boundary between them?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">It is more of a transition zone than a boundary. The gravitational potential of the Sun at Earth's surface is stronger than the gravitational potential of the Earth. So Earth simply adds roughly 10% to the local potential from the Sun, which in turn just adds to the background from the Galaxy, etc. Local gravity operates on this potential medium (elysium) just as it would operate on any other contiguous medium. Changes in the density of the medium at any point are directly proportional to changes in the sums of all operating potentials.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Do you think that a reference frame with zero gravitational potential can be used as the absolute still reference frame?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Remember that the "zero" of gravitational potential is arbitrary. Any constant can be added. Only changes in potentials have local effects.

Likewise, the background elysium density can be any arbitrarily large value. Then masses simply add local density to that large background density.

In the Meta Model, defining a "still reference frame" for elysium would be as difficult as an airborn dust particle defining a still reference frame for the surrounding local air. Think of elysium as just the "local" atmosphere of a mega-planet, limited in extent and having an arbitrary speed through space. You can then see the futility of trying to define an absolute frame of reference.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">In this frame, the speed of light will reach a maximum limit.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Whatever the background density of elysium, the speed of light would be faster in elysium of even lower density. For example, maybe elysium is like our atmosphere and decreases in density with "altitude". In the case of elysium, this might be altitude above a mega planet composed of galaxy-sized atoms.

Any wave phenomenon's propagation speed will increase without limit as its carrying medium decreases in density toward zero. -|Tom|-

The general equation for the speed of a wave in some medium is:

... speed_of_wave = sqrt(stiffness_of_medium / density_of_medium)

This assumes that other variables, such as temperature, do not change.

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In theory, if density actually becomes zero the speed of a wave will be undefined by this this model.

In practice, wave like behavior fails at some point above zero density because the particles of the medium have to travel too far (more than a wave length) to collide with another particle.

Regards,
LB

I sometimes criticize others for being lazy about units. Mostly I do this when someone makes a glaring mistake that would have been obvious if only they had included units in their analysis.

I actually did check my units before I posted (because I really do want to avoid making the kind of blooper that often occurs when one does not check units). But I guess I ought to stop being lazy as well and include the unit analysis when I post.

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... speed_of_wave = sqrt(stiffness_of_medium / density_of_medium)

... [m/sec] = sqrt( [nt/m^2] / [kg/m^3] )

where [nt] = [kg]*[m/sec^2]
(good ole f = m*a)

LB

Dear Mr. Flandern,
When the light travels in the sun’s frame, its speed is relative to the gravitational potential field of the sun. When it enters the earth’s frame, its speed is relative to the gravitational field of the earth. But if there is a transit zone in between, how do you define the speed of light in this zone?
Zero gravitational potential means that the LCM is far away enough from any gravitational centre; so the property of the LCM is the same everywhere. In this case, do you think that the speed of light should reach a maximum limit?